Exemplary embodiments of the present invention relate to technology for transmitting and receiving data.
In general, jitter effects in high-speed data transmission include random jitter effects with inter symbol interference (ISI). Among them, cross talk has the greatest effect upon the data transmission.
FIG. 1 is a diagram illustrating a case in which cross talk occurs on a plurality of parallel lines LINE0 to LINE3 through which data are transmitted. The left-side data are first loaded on the lines LINE0 to LINE3, and the right-side data are later loaded on the lines LINE0 to LINE3.
The cross talk occurs due to a capacitance generated between adjacent lines. The effects caused by the cross talk become severe when the change in value of the data of adjacent lines is opposite to the change in value of the data of a center line therebetween. In other words, cross talk is severe where the voltage levels of two outside lines increases or decreases, while the voltage level of a center line between the two outside lines decreases or increases, respectively. In such a case, the data pattern is referred to as a two-aggressors and one-victim pattern.
In FIG. 1, reference numerals 101, 102, 103, 104, and 105 each indicate a case in which a two-agressors and one-victim pattern occurs. Referring to reference numeral 101, the data of the line LINE1 changes from low to high (L-H), but the data of the lines LINE0 and LINE2 change from high to low (H-L). In this case, the data of the line LINE1 may have difficulty changing due to the occurrence of cross talk. Similarly, referring to reference numerals 102, 103, and 105, the change in value of the data of the center line is opposite to the change in value of the data of adjacent lines on both sides of the center line. Therefore, in each of the scenarios designated by reference numerals 102, 103, and 105, the data of the center line may have difficulty changing.
Referring to reference numeral 104, the adjacent lines of both lines LINE1 and LINE2 have data that change in an opposite direction. Therefore, in the scenario designated by reference numeral 104, the data of both lines LINE1 and LINE2 may have difficulty changing.
FIG. 2 is a diagram showing a difference in jitter between data of a two-aggressors and one-victim pattern and data of a one-aggressor pattern. In the one-aggressor pattern, a line has only one adjacent line that undergoes a change in data that is opposite its change in data.
As shown in FIG. 2, the one-aggressor pattern data has a jitter of 29.6 ps, but the two-aggressors and one-victim pattern data has a jitter of 56.9 ps.
When such a jitter caused by the cross talk is not removed, it is difficult to transmit data at a high speed without an error.